Friday, April 30, 2010

With just a half second's notice, a driver can swerve to avoid a fatal accident or slam on the brakes to miss hitting a child running after a ball. But first, the driver must perceive the danger.

Research shows that a rapid alert system can help mitigate the risks, fatalities and severe injuries from road accidents, says Prof. Shai Avidan of Tel Aviv University's Faculty of Engineering. He is currently collaborating with researchers from General Motors Research Israel to keep cars on the road and people out of hospitals.

An expert in image processing, Prof. Avidan and his team are working to develop advanced algorithms that will help cameras mounted on GM cars detect threats, alerting drivers to make split-second decisions. His research has been published in leading journals, including the IEEE Transaction on Pattern Analysis and Machine Intelligence and featured at conferences in the field.

The challenge, says Prof. Avidan, is to develop a system that can recognize people, distinguishing them from other moving objects — and to create a model that can react almost instantaneously. Ultimately, he is hoping computer vision research will make cars smarter, and roads a lot safer.

Cars are not much different from one another. They all have engines, seats, and steering wheels. But new products are adding another dimension by making cars more intelligent. One such product is the smart camera system by MobilEye, an Israeli startup company. Prof. Avidan was part of the MobilEye technical team that developed a system to detect vehicles and track them in real-time.

He is now extending that research to develop the next generation of smart cameras — cameras that are aware of their surroundings. His goal is a camera capable of distinguishing pedestrians from other moving objects that can then warn the driver of an impending accident.

The challenge is in the development of a method that can detect and categorize moving objects reliably and quickly. Prof. Avidan hopes to realize such a method by combining powerful algorithms to recognize and track objects. Such a tool could double check for vehicles in your blind spot, help you swerve when a child runs into the street, or automatically block your door from opening if a cyclist is racing toward you, he says.

Eventually, he hopes cameras will be able to recognize just about anything moving through the physical world, offering a tantalizing vision of applications such as autonomous vehicles. The underlying technology could also be used in computer gaming to track a player's movements, or for surveillance to detect a potential intruder.

Previously, detection systems used radar, which is expensive and not particularly sensitive to human beings. A smart camera fuelled by a powerful chip, on the other hand, could detect the activities of people and animals, and prompt the car to react accordingly, braking more or locking the doors, for example.

To date, Prof. Avidan has demonstrated that his technology works on infrared, greyscale, and color cameras. "Cameras are quite dumb machines unless you know how to extract information from them," he says. "Now, as the price of cameras drop and computer power grows, we'll see more exciting applications that will keep us safe and make our lives more comfortable."

When we like a product, do we think others will like it, too? And when we believe others like a product, do we like it as well? A new study in the Journal of Consumer Research says these two questions are fundamentally different.

"The answer to the first question (Will others like it?) requires people to start with their own product preferences, which we call projection," write authors Caglar Irmak (University of South Carolina), Beth Vallen (Loyola University), and Sankar Sen (Baruch College). The second question (If others like it, do I?) makes people think first about others' preferences and then decide whether they like the product or not, which is called "introjection."

"We show that different psychological processes underlie projection and introjection," the authors write. "In particular, we demonstrate that providing our own opinion about a product before thinking about others' preferences, as in projection, affirms one's unique concept." This, in turn, weakens uniqueness motivations and leads consumers to predict others will like what they themselves like.

On the other hand, thinking about others' preferences before our own (introjection) threatens our sense of uniqueness. "As a result, those who are in high need for uniqueness don't like what other people like," the authors explain.

In their studies, the authors showed participants advertisements for one of two novel technology products that had not yet been introduced to the market. One group of participants, assigned to the projection condition, stated their own preferences for the product and then estimated those of others. Another group, which was assigned the introjection condition, estimated the preferences of others and then reported their own preferences. Then they measured the participants' need for uniqueness.

"If we learn others' preferences before forming our own, we tend to preserve our uniqueness by altering our product preferences accordingly," the authors write. "If, however, we already have an opinion about a product, we are okay with others following us."

In order to make electric cars a part of everyday life, new vehicle designs and parts are needed. Take wheel hub motors, for instance. One of the advantages of wheel hub motors is that manufacturers can dispense with the conventional engine bay – the space under the »hood« or »bonnet« – since the motors are attached directly to the wheels of the vehicle. This opens up a wealth of opportunities for car designers when drafting the layout of the vehicle. Additional advantages: By dispensing with the transmission and differential, the mechanical transmission elements suffer no losses or wear and tear. Moreover, the direct drive on each individual wheel may improve the drive dynamic and drive safety.

Researchers are developing not only individual components, but the total system as well. They assemble the components on their concept car, known as the »Frecc0« or the »Fraunhofer E-Concept Car Type 0« – a scientific test platform. Starting next year, automobile manufacturers and suppliers will also be able to use the »Frecc0« for testing new components. The basis of this demo model is an existing car: The new Artega GT manufactured by Artega Automobil GmbH. The establishment of this platform and the engineering of the wheel hub motor are just two projects among the panoply run by »Fraunhofer System Research for Electromobility«. The research cooperative is focusing on subjects that include vehicle design, energy production, distribution and implementation, energy storage techniques, technical system integration and sociopolitical matters. The federal ministry for education and research BMBF is funding this Fraunhofer initiative with 44 million euro. The goal is to develop prototypes for hybrid and electric vehicles, in order to support the German automotive industry as it makes the crossover to electromobility.

Wheel hub motors were invented back in the 19th century. Ferdinand Porsche used these motors to equip his »Lohner Porsche« at the 1900 World Fair in Paris. Much has been done since then: »We are developing a wheel hub motor that integrates all essential electric and electronic components, especially the power electronics and electronic control systems, into the installation space of the motor. Thus, no external electronics are necessary and the number and scope of the feed lines can be minimized. There is a marked increase in power compared to the wheel hub motors currently available on the market. Moreover, there is an innovative security and redundancy concept, which guarantees drive safety – even if the system breaks down,« explains Professor Matthias Busse, head of the Fraunhofer Institute for Manufacturing Engineering and Applied Materials Research IFAM. Beside IFAM, researchers from the Fraunhofer Institute for Integrated Systems and Device Technology IISB, for Mechanics of Materials IWM and for Structural Durability and System Reliability LBF are tackling these issues.

Critics find fault with the negative effects of wheel hub motors on vehicle handling. Dr. Hermann Pleteit, IFM project manager, responds: »The motor is extremely compact. The high power and torque densities merely cause a relatively low increase in unsprung mass. But by configuring the chassis in different ways – like the muffler settings, for example - you can compensate for these effects. There is no impact on drive comfort.«

The researchers are meeting yet another challenge: In contrast to conventional vehicles, electric cars can recapture the energy that comes from braking, and feed it back into the battery. In this case, the experts refer to »recuperation«. Now they are working on maximizing this energy recapture in the future. The conventional braking system still in use will only be needed in emergency situations.

With the Fraunhofer wheel hub motor, the researchers are implementing Ferdinand Porsche's idea for the cars of the future, and testing these components on the demonstration vehicle.

As the solar wind flows over natural obstructions on the moon, it may charge polar lunar craters to hundreds of volts, according to new calculations by NASA's Lunar Science Institute team.

Polar lunar craters are of interest because of resources, including water ice, which exist there. The moon's orientation to the sun keeps the bottoms of polar craters in permanent shadow, allowing temperatures there to plunge below minus 400 degrees Fahrenheit, cold enough to store volatile material like water for billions of years. "However, our research suggests that, in addition to the wicked cold, explorers and robots at the bottoms of polar lunar craters may have to contend with a complex electrical environment as well, which can affect surface chemistry, static discharge, and dust cling," said William Farrell of NASA's Goddard Space Flight Center, Greenbelt, Md. Farrell is lead author of a paper on this research published March 24 in the Journal of Geophysical Research. The research is part of the Lunar Science Institute's Dynamic Response of the Environment at the moon (DREAM) project.

"This important work by Dr. Farrell and his team is further evidence that our view on the moon has changed dramatically in recent years," said Gregory Schmidt, deputy director of the NASA Lunar Science Institute at NASA's Ames Research Center, Moffett Field, Calif. "It has a dynamic and fascinating environment that we are only beginning to understand."

Solar wind inflow into craters can erode the surface, which affects recently discovered water molecules. Static discharge could short out sensitive equipment, while the sticky and extremely abrasive lunar dust could wear out spacesuits and may be hazardous if tracked inside spacecraft and inhaled over long periods.

The solar wind is a thin gas of electrically charged components of atoms -- negatively charged electrons and positively charged ions -- that is constantly blowing from the surface of the sun into space. Since the moon is only slightly tilted compared to the sun, the solar wind flows almost horizontally over the lunar surface at the poles and along the region where day transitions to night, called the terminator.

The researchers created computer simulations to discover what happens when the solar wind flows over the rims of polar craters. They discovered that in some ways, the solar wind behaves like wind on Earth -- flowing into deep polar valleys and crater floors. Unlike wind on Earth, the dual electron-ion composition of the solar wind may create an unusual electric charge on the side of the mountain or crater wall; that is, on the inside of the rim directly below the solar wind flow.

Since electrons are over 1,000 times lighter than ions, the lighter electrons in the solar wind rush into a lunar crater or valley ahead of the heavy ions, creating a negatively charged region inside the crater. The ions eventually catch up, but rain into the crater at consistently lower concentrations than that of the electrons. This imbalance in the crater makes the inside walls and floor acquire a negative electric charge. The calculations reveal that the electron/ion separation effect is most extreme on a crater's leeward edge – along the inside crater wall and at the crater floor nearest the solar wind flow. Along this inner edge, the heavy ions have the greatest difficulty getting to the surface. Compared to the electrons, they act like a tractor-trailer struggling to follow a motorcycle; they just can't make as sharp a turn over the mountain top as the electrons. "The electrons build up an electron cloud on this leeward edge of the crater wall and floor, which can create an unusually large negative charge of a few hundred Volts relative to the dense solar wind flowing over the top," says Farrell.

The negative charge along this leeward edge won't build up indefinitely. Eventually, the attraction between the negatively charged region and positive ions in the solar wind will cause some other unusual electric current to flow. The team believes one possible source for this current could be negatively charged dust that is repelled by the negatively charged surface, gets levitated and flows away from this highly charged region. "The Apollo astronauts in the orbiting Command Module saw faint rays on the lunar horizon during sunrise that might have been scattered light from electrically lofted dust," said Farrell. "Additionally, the Apollo 17 mission landed at a site similar to a crater environment – the Taurus-Littrow valley. The Lunar Ejecta and Meteorite Experiment left by the Apollo 17 astronauts detected impacts from dust at terminator crossings where the solar wind is nearly-horizontal flowing, similar to the situation over polar craters."

Next steps for the team include more complex computer models. "We want to develop a fully three-dimensional model to examine the effects of solar wind expansion around the edges of a mountain. We now examine the vertical expansion, but we want to also know what happens horizontally," said Farrell. As early as 2012, NASA will launch the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission that will orbit the moon and could look for the dust flows predicted by the team's research.

Richard Borgens and his colleagues from the Center for Paralysis Research at the Purdue School of Veterinary Medicine have a strong record of inventing therapies for treating nerve damage. From Ampyra, which improves walking in multiple sclerosis patients to a spinal cord simulator for spinal injury victims, Borgens has had a hand in developing therapies that directly impact patients and their quality of life. Another therapy that is currently undergoing testing is the use of polyethylene glycol (PEG) to seal and repair damaged spinal cord nerve cells. By repairing the damaged membranes of nerve cells, Borgens and his team can restore the spinal cord's ability to transmit signals to the brain. However, there is one possible clinical drawback: PEG's breakdown products are potentially toxic. Is there a biodegradable non-toxic compound that is equally effective at targeting and repairing damaged nerve membranes?

Borgens teamed up with physiologist Riyi Shi and chemist Youngnam Cho, who pointed out that some sugars are capable of targeting damaged membranes. Could they find a sugar that restored spinal cord activity as effectively as PEG? Borgens and his team publish their discovery that chitosan can repair damaged nerve cell membranes in The Journal of Experimental Biology on 16 April 2010 at http://jeb.biologists.org/.

Having initially tested mannose and found that it did not repair spinal cord nerve membranes, Cho decided to test a modified form of chitin, one of the most common sugars that is found in crustacean shells. Converting chitin into chitosan, Cho isolated a segment of guinea pig spinal cord, compressed a section, applied the modified chitin and then added a fluorescent dye that could only enter the cells through damaged membranes. If the chitosan repaired the crushed membranes then the spinal cord tissue would be unstained, but if the chitosan had failed, the spinal cord neurons would be flooded with the fluorescent dye. Viewing a section of the spinal cord under the microscope, Cho was amazed to see that the spinal cord was completely dark. None of the dye had entered the nerve cells. Chitosan had repaired the damaged cell membranes.

Next Cho tested whether a dose of chitosan could prevent large molecules from leaking from damaged spinal cord cells. Testing for the presence of the colossal enzyme lactate dehydrogenase (LDH), Borgens admits he was amazed to see that levels of LDH leakage from chitosan treated spinal cord were lower than from undamaged spinal cords. Not only had the sugar repaired membranes at the compression site but also at other sites where the cell membranes were broken due to handling. And when the duo tested for the presence of harmful reactive oxygen species (ROS), released when ATP generating mitochondria are damaged, they found that ROS levels also fell after applying chitosan to the damaged tissue: chitosan probably repairs mitochondrial membranes as well as the nerve cell membranes.

But could chitosan restore the spinal cord's ability to transmit electrical signals to the brain through a damaged region? Measuring the brain's response to nerve signals generated in a guinea pig's hind leg, the duo saw that the signals were unable to reach the brain through a damaged spinal cord. However, 30•min after injecting chitosan into the rodents, the signals miraculously returned to the animals' brains. Chitosan was able to repair the damaged spinal cord so that it could carry signals from the animal's body to its brain.

Borgens is extremely excited by this discovery that chitosan is able to locate and repair damaged spinal cord tissue and is even more enthusiastic by the prospect that nanoparticles of chitosan could also target delivery of neuroprotective drugs directly to the site of injury 'giving us a dual bang for our buck,' says Borgens.

The eerie glow that straddles the night time zodiac in the eastern sky is no longer a mystery. First explained by Joshua Childrey in 1661 as sunlight scattered in our direction by dust particles in the solar system, the source of that dust was long debated. In a paper appeared in the April 20 issue of The Astrophysical Journal, David Nesvorny and Peter Jenniskens put the stake in asteroids. More than 85 percent of the dust, they conclude, originated from Jupiter Family comets, not asteroids.

"This is the first fully dynamical model of the zodiacal cloud," says planetary scientist Nesvorny of the Southwest Research Institute in Boulder, Colo. "We find that the dust of asteroids is not stirred up enough over its lifetime to make the zodiacal dust cloud as thick as observed. Only the dust of short-period comets is scattered enough by Jupiter to do so."

This result confirms what meteor astronomer Jenniskens of the SETI Institute in Mountain View, Calif., had long suspected. An expert on meteor showers, he had noticed that most consist of dust moving in orbits similar to those of Jupiter Family comets, but without having active dust-oozing comets associated with them.

Instead, Jenniskens discovered a dormant comet in the Quadrantid meteor shower in 2003 and has since identified a number of other such parent bodies. While most are inactive in their present orbit around the Sun, all have in common that they broke apart violently at some point in time in the past few thousand years, creating dust streams that now have migrated into Earth's path.

Nesvorny and Jenniskens, with the help of Harold Levison and William Bottke of the Southwest Research Institute, David Vokrouhlicky of the Institute of Astronomy at Charles University in Prague, and Matthieu Gounelle of the Natural History Museum in Paris, demonstrated that these comet disruptions can account for the observed thickness of the dust layer in the zodiacal cloud.

In doing so, they solved another mystery. It was long known that snow in Antarctica is laced with micro-meteorites, some 80 to 90 percent of which have a peculiar primitive composition, rare among the larger meteorites that we know originated from asteroids. Instead, Nesvorny and Jenniskens suggest that most antarctic micro-meteorites are pieces of comets. According to their calculations, cometary grains dive into Earth's atmosphere at entry speeds low enough for them to survive, reach the ground, and be picked up later by a curious micro-meteorite hunter.